### More Examples

*“What was the nonce for the last bitcoin block?”*

*“A nonce can only be used once.”*

*“Finding the correct nonce in a bitcoin block constitutes proof-of-work.”*

### Definition(s) from the Web

- The “nonce” in a bitcoin block is a 32-bit (4-byte) field whose value is adjusted by miners so that the hash of the block will be less than or equal to the current target of the network. The rest of the fields may not be changed, as they have a defined meaning. Any change to the block data (such as the nonce) will make the block hash completely different. Since it is believed infeasible to predict which combination of bits will result in the right hash, many different nonce values are tried, and the hash is recomputed for each value until a hash less than or equal to the current target of the network is found. The target required is also represented as the difficulty, where a higher difficulty represents a lower target. As this iterative calculation requires time and resources, the presentation of the block with the correct nonce value constitutes proof of work. Source
- Nonce – a number that can only be used once – in cryptography is a one-time code, vibrant overcome or pseudorandom manner, which is used to biopsy the main to do transmission, preventing to take the power of reproduction. In Bitcoin’s mining process, the goal is to find a hash below a target number which is calculated based on the difficulty. Proof-of-work in Bitcoin’s mining takes an input consists of Merkle Root, timestamp, previous block hash and few other things plus a nonce which is completely random number. If the output results in hash is smaller than the target hash you win the block and the consensus is reached. You need to brute force all possible nonce in order to luckily find a hash smaller than the target hash. Source
- In cryptography, a nonce is an arbitrary number that can be used just once in a cryptographic communication. It is similar in spirit to a nonce word, hence the name. It is often a random or pseudo-random number issued in an authentication protocol to ensure that old communications cannot be reused in replay attacks. They can also be useful as initialisation vectors and in cryptographic hash functions. Source